When a guy thinks a girl wants to be romantically involved with him because she is nice to him and wants to hang out with him, but in reality she just thinks of him in a platonic way, like a "bro". Hence the "bromance"

You could say that a guy has a case of the bromance when he develops a crush on a friend that is a girl.

You could also say that a girl is plagued by bromance when all her guy friends tend to fall in love with her.

Emilie: Shit, Dave's been texting me like twenty times a day. Its starting to get annoying.

The deepest friendship two guys can have,they may seem homosexual ,but they aren't and will get very offended if you call them gay,it usually consists of telling each other deep secrets or gossip,and maybe a hug or two and share a deep emontional bond

person 1:Dave and Tim must be gay! look at them
person 2:no they're in a bromance